Injection molds commonly include a sprue bushing housed in a bore provided in one or more mold plates of the mold assembly. The sprue bushing extends through the mold plates and includes one end communicating with the mold cavity. An injection nozzle seats against one end of the sprue bushing, and the sprue bushing provides flow of molten material from the injection nozzle to the mold cavity. An example of such a mold apparatus is illustrated in the Von Holdt U.S. Pat. No. 4,289,473, issued Sept. 15, 1981. With such apparatus alignment of the relative position of the sprue bushing and the mold cavity is important to provide proper flow into the mold cavity. The sprue bushing commonly includes one or more discharge openings intended to be aligned with runners of the mold cavity. Misalignment of the discharge openings and the runners will result in improper or incomplete injection of plastic into the mold cavity.
One prior art method for securing the sprue bushing in place with respect to the mold plate is to provide the sprue bushing with a peripheral flange and to provide apertures in the peripheral flange such that bolts can extend through the flange and secure the sprue bushing to the mold plate.
In other prior art arrangements bores are drilled between the periphery of the sprue bushing and the mold plate, and dowels or keys are housed in the bores to secure the sprue bushing in place with respect to the mold plate.
Attention is also directed to the Hartmann U.S. Pat. No. 3,897,929; the Czerski U.S. Pat. No. 3,698,849; the Babiol U.S. Pat. No. 4,428,725; the Putkowski U.S. Pat. No. 3,677,682; the Adair et al. U.S. Pat. No. 3,443,001; and the Dulmate U.S. Pat. No. 3,109,201.